devilbiss hf5030-wk - unloader valve problem?

I think I have a bad unloader valve or pressure switch.


the compressor runs fine with no load but once it gets to around 80psi if it stops it really struggles and blows a fuse when it starts up again.

I can hear the psssst noise from the unloader valve when it shuts off - so does that mean the unloader valve is working correctly and the problem is somewhere else or is it a bad unloader valve? Its a devilbiss hf5030-wk.
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If you hear the unloader valve work when the air pressure in the tank reaches cut out, then, it's working, and is not likely your compressor problem.

Why does your air compressor stop at 80 PSI though? That seems to me to be a pretty low cut out pressure level. Is that the cut out pressure, or can the motor not continue to drive the pump past that pressure?

Cheers,

Bill



Comments for devilbiss hf5030-wk - unloader valve problem?

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Feb 23, 2012
bad motor or pressure switch?
by: Anonymous

Still a little confused...when I turn it off manually around 80psi, I hear the unloader valve working by letting out some of the air, but if i then turn it back on it struggles and blows the fuse. If I have 0 or under around 80 psi and I turn it off and restart, it starts up and runs fine. so I think the unloader valve is working fine so is it a bad motor or bad pressure switch or something else?
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Then I suspect the start capacitor. Can you check it out?

Feb 23, 2012
reply on hf5030-wk
by: Anonymous

thanks for the answer bill- I think it will still turn off automatically at around 125 psi- but when the psi drops or if I turn it off manually at around 80 -100 psi- then turn it back on again- thats when its struggling to start up and pulling a lot of current and then trips the fuse. I have tested both capacitors and they are ok- I am starting to think its the motor going bad?
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When you shut it off at 80 PSI or whatever, you are overriding the pressure switch, and, power should still be flowing to the motor circuit through the switch, so when you turn the compressor back on, it should start... unless, when you turn the compressor off manually, the unloader doesn't trigger. Then, you've got air trapped over the piston, and that adds to start load.

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Compressor 44643 how to set valves

by MarkDaigle
(East Bernard Texas)

I am an Ag teacher in Texas, we overhauled a DeVilbiss 44643. It will not build any pressure.

We put new ring and one piston and rod, and also valve kits in.

I am thinking it is with the valves, just don't know how to set them.

Any suggestions. Thanks, Mark

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DeVilbiss air compressor makes knocking noise that gets louder and louder as tank air pressure builds

by Robert Glines
(El Monte, Ca.)

I have a problem with a Devilbiss air compressor that when it starts up, it sounds normal, but, as the pressure builds up in the tank, it emits a knocking noise that gets progressively worse.

We inspected the valves inside the cylinder head, and saw that nothing was broken, although they were a little dirty.

We also ran that compressor with the head off, to see if there was any obvious noise coming from the shaft bearing, or any of the other parts inside the crankcase, and it was quiet.

I believe that at this point, the compressor needs to be changed out. Please advise.

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Bill says...

Robert, based on the information in your post, I would surmise that you have a bearing that is failing under load.

Double check the mounting bolts, and the belt alignment too.

Cheers,

Bill

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Rotation of Devilbiss compressor motor

I replaced the motor on my 5 hp 60 gal compressor. the original motor ran clockwise looking at the pulley but this one runs counter clockwise, the arrow on the compressor fan/pulley shows this to be the proper rotation and compressor seems to work fine.

dose the rotation matter? and is it possible that the factory motor was wrong all these past 8 years?

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Dec 11, 2013
rotation
by: Doug in s.d.ca

anything is possible.

It seems that for a piston type, it doesn't really matter.

Perhaps there is a cooling advantage vis-a-vis the pully rotation, and it sounds like maybe yours might run a tad cooler now, with the air being forced toward the compressor instead of being drawn away, if I understand you correctly.

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